calibrating temp question

is there a calculator that can generate a new temp table if i know what the difference is between how hot the printer thinks it is and how hot it actually is?

when i set my printer nozzle to 185 the actual temp is 164 I am measuring actual temps with a extech EX330 multimeter with a type k thermocouple.

i think my thermisistors are 100k but they were in a junk drawer so i really have no clue what they are.

also interested in doing this with my heated bed but i want to calibrate on the surface of the glass (it will be off in terms of the correct temp displayed but i am ok with that) the thermisistor is on the bottom of the pcb. the bed will be hotter than the surface but i would like to make it so when the surface reaches 125 then the heater shuts off.

anything out there that will do this? I could jsut figure it out and put in wildly different numbers to get the desired results but it would be nice if it were calibrated.

i am using ramps 1.2, teacup firmware and a nichrome makergear hot end with standard prusa hbp.

thanks
t

Edited 1 time(s). Last edit at 05/21/2012 08:47PM by zg_bot.

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i think my thermisistors are 100k but they were in a junk drawer so i really have no clue what they are.

Measure them? At 25°C you can measure the reference resistance with a simple ohms meter.

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teacup firmware

Look into ThermistorTable.double.h. There's a description on how to get accurate measurements. Some 15 value pairs should be sufficient, though; the currently 102 pairs there are simply a memory and processing time waste.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

thanks

thats a bummer, its really amazing how hard it is to get one of these machines running properly.

Many people simply ignore the difference between measured temperature and actual temperature. As long as the temperature is kept reasonably constant, it doesn't matter wether the value shown is "180" or "215".

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Generation 7 Electronics	Teacup Firmware	RepRap DIY